Predictors of lower extremity arterial injury after total knee or total hip arthroplasty.

Objective: Lower extremity arterial injury is a rare complication following total knee (TKA) or total hip arthroplasty (THA). To date, no multi-institutional study has identified preoperative factors that may portend increased risk for these injuries. We queried a large clinical database for the incidence and predictors of arterial injury and/or compromise following lower extremity arthroplasty.

Effect of folic acid and vitamins B6 and B12 on microcirculatory vasoreactivity in patients with hyperhomocysteinemia.

Objective: Hyperhomocysteinemia (HHcy) has been identified as an independent risk factor for atherosclerotic vascular disease. The effect of high-dose folic acid or combination vitamin therapy for the treatment of HHcy on the microcirculation is unknown. The purpose of this study was to evaluate the effect of a combination of folic acid, vitamin B6, and vitamin B12 on endothelium-dependent and endothelium-independent vasoreactivity in patientswith HHcy.

The effects of the type of anesthesia on outcomes of lower extremity infrainguinal bypass.

Objective: Three main types of anesthesia are used for infrainguinal bypass: general endotracheal anesthesia (GETA), spinal anesthesia (SA), and epidural anesthesia (EA). We analyzed a large clinical database to determine whether the type of anesthesia had any effect on clinical outcomes in lower extremity bypass.

Methods: This study is an analysis of a prospectively collected database by the National Surgical Quality Improvement Program (NSQIP) of the Veterans Affairs Medical Centers.

Hypoxia attenuates insulin-induced proliferation and migration of human diabetic infrapopliteal vascular smooth muscle cells.

The proliferative effects of insulin on infrapopliteal vascular smooth muscle cells (VSMCs) have been established. We examined the effect of hypoxia in the presence and absence of insulin on the proliferation and migration of human diabetic infrapopliteal VSMCs in vitro. VSMCs isolated from the infrapopliteal arteries of male diabetic patients of identical disease and clinical patterns undergoing below-knee amputation were harvested and grown to subconfluence.

Thiamine (vitamin B1) improves endothelium-dependent vasodilatation in the presence of hyperglycemia.

Brachial artery vasoactivity (BAVA) is a reliable, noninvasive method of assessing endothelium-dependent vasodilatation (EDV) in vivo. Acute hyperglycemia, impaired glucose tolerance (IGT), and diabetes mellitus impair EDV, a precursor to atherosclerosis. Thiamine is a coenzyme important in intracellular glucose metabolism.

Carotid plaque morphologic characteristics.

Carotid artery atherosclerosis is predominantly believed to mirror atherosclerosis elsewhere in the body. Endothelial injury results in expression of cell surface adhesion molecules with expression of sequence of genes involved in the inflammatory pathway and expression of proinflammatory cytokines. The combination of the inflammatory mediators and contribution by monocytes infiltrating the intima and vascular smooth muscle cell proliferation result in the development of atheromatous plaque with a lipid-rich necrotic core.

Evaluation of macrocirculatory endothelium-dependent and endothelium-independent vasoreactivity in vascular disease.

Macrocirculatory endothelium-dependent and independent vasodilatation is integral to tissue-bed oxygen delivery and homeostasis. Dysfunction of macrocirculatory vasoreactivity is a precursor to atherosclerosis and occurs in a similar fashion in multiple tissue beds long before the onset of symptoms. Impaired macrocirculatory vasodilatation has been shown to occur in certain disease states including diabetes mellitus, hypercholesterolemia, chronic renal failure, peripheral arterial atherosclerosis, and abdominal aortic aneurysms, as well as secondary to smoking, advanced age, menopause, high-fat diet, and sedentary lifestyle.

Evaluation of the microcirculation in vascular disease.

Insufficient blood flow through end-resistance arteries leads to symptoms associated with peripheral vascular disease. This may be caused in part by poor macrocirculatory inflow or impaired microcirculatory function. Dysfunction of the microcirculation occurs in a similar fashion in multiple tissue beds long before the onset of atherosclerotic symptoms.

Aortic angiosarcoma presenting as distal arterial embolization.

Aortic angiosarcoma is a rare, malignant neoplasm of the vasculature, with 24 case reports in the literature. Patients usually present with either aneurysmal or occlusive disease. Treatment consists of en bloc resection of the vessel and contiguous structures with postoperative chemoradiation therapy.

Medical factors affecting patency of arteriovenous access.

Arteriovenous access failure is multifactorial in nature with contributions from both medical and surgical etiologies. Medical causes of arteriovenous access failure are rare, and therefore infrequently identified as a major contributing source of malfunction. Although they account for only 10-15% of all cases of access failure, their importance should not be underestimated, especially in cases where a surgical source cannot be identified.

Strategies of arteriovenous dialysis access.

Surgical management of the patient who requires hemodialysis access, while continuing to demand more attention from the vascular surgeon, suffers from discrepancies of approach and strategy. With the increase in incidence of dialysis dependent renal failure among our population, many have attempted to present a uniform, logical strategy with which the vascular surgeon can most effectively treat the hemodialysis patient in the long term. Most notably, the multidisciplinary Dialysis Outcomes Quality Initiative (DOQI) guidelines present the surgeon with a rough outline of hemodialysis access insertion strategy, and it has become nationally recognized as an acceptable summary of treatment strategy and goals.

Transcatheter embolization of extremity vascular malformations: the long-term success of multiple interventions.

Vascular malformations of the extremities present a difficult therapeutic challenge. Ligation of feeding vessels may lead to tissue necrosis and limb loss and can make subsequent attempts at transcatheter therapy impossible. The purpose of this study was to review our results with transcatheter embolization therapy in symptomatic vascular malformations in the upper and lower extremities in 50 patients.

Syndrome X and diabetes: what is the mystery?

Syndrome X describes a combination of clinical phenomena that have been statistically linked to hyperinsulinema in the absence of frank diabetes. Since its original description, Syndrome X has come to represent several phenotypes that have hemodynamic and metabolic effects on the individual, as well as major effects on the development of vascular disease. Further, this syndrome is reaching epidemic proportions, As such, a thorough understanding of this condition is becoming increasingly important for the modern vascular surgeon.

Aneurysm morphology as a predictor of endoleak following endovascular aortic aneurysm repair: do smaller aneurysm have better outcomes?

Since the Food and Drug Administrations' approval of endovascular devices for abdominal aortic aneurysm (AAA) repair, clinicians have been relaxing the strict inclusion criteria present during the clinical trials. Although the long-term natural history of endoleaks remains unclear, attachment site leaks (type I) are believed to represent an ongoing risk for future rupture. We reviewed our experience with endovascular AAA repair to elucidate factors that predispose toward the development of endoleaks and found that larger AAAs are significantly more likely to have a short proximal neck and severe proximal angulation.

Peripheral vascular brachytherapy.

Ongoing advances in peripheral endovascular technology have been met with disappointing results because of restenosis within the treated vessel. In particular, stent balloon angioplasty of peripheral vessels has yet to achieve patency rates that approximate conventional treatment in the long term. Recent advances in stent, balloon, and wire construction include the incorporation of radioactive substances in an attempt to ameliorate the inflammatory response provoked by typical endovascular manipulation, a technique termed vascular brachytherapy.

Are type II (branch vessel) endoleaks really benign?

The natural history and clinical significance of type II or branch vessel endoleaks following endovascular aortic aneurysm (AAA) repair remain unclear. Some investigators have suggested that these endoleaks have a benign course and outcome and that they can be safely observed. The purpose of this study was to document the natural history and outcome of all type II endoleaks that have occurred following endovascular AAA repair at our institution.

Pressure- versus volume-cycled ventilation in liquid-ventilated neonatal piglet lungs.

Background/purpose: If the goal of partial liquid ventilation (PLV) with perfluorocarbons in the management of respiratory failure is to improve dynamic lung compliance (Cdyn) and pulmonary vascular resistance (PVR) while sustaining O2 delivery, the optimal ventilatory management is unclear. The authors asked if volume-cycled or pressure-limited ventilation had different effects on PVR, cardiac index (CI), and Cdyn in uninjured and injured neonatal piglet lungs.

Methods: Anesthetized piglets (6 to 8 kg) were ventilated after tracheostomy.

Changes in pulmonary vascular resistance in response to partial liquid ventilation.

Background/purpose: Partial liquid ventilation (PLV) with perfluorocarbons decreases pulmonary vascular resistance (PVR) in injured piglet lungs without supplemental oxygen. These PVR changes may result either from direct mechanical effects or improved arterial oxygenation. In an uninjured hypoxic model of elevated PVR the authors asked the following questions: (1) Does prophylactic or therapeutic PLV ameliorate the PVR response to hypoxia? (2) Do prophylactic and therapeutic PLV have different PVR effects? (3) Does supplemental oxygen modify PVR response to PLV?

Methods: Piglet (3 to 4 kg) lungs were isolated in situ without ischemia, hypoxia, or reperfusion injury.

Partial liquid ventilation (PLV) and lung injury: is PLV able to modify pulmonary vascular resistance?

Introduction: Partial liquid ventilation (PLV) with perfluorocarbons can be advantageous in treating lung injury. We studied this phenomenon in isolated piglet lungs devoid of systemic detractors by studying the changes in pulmonary vascular resistance (PVR) after lung injury with and without PLV. The following questions were asked.

Complex colon duplication mimicking an obstructed, non-functioning kidney in a newborn with imperforate anus and spinal dysraphism.

Gastrointestinal (GI) duplications contain tissue resembling several portions of the GI tract and are associated with vertebral and genitourinary (GU) abnormalities [1-4]. We report a newborn with low, imperforate anus and lumbosacral dysraphism, who presented with a large cystic mass in the left renal fossa and pelvis. The flank mass (felt initially to be a dysplastic kidney and ureter) proved to be a complex GI duplication with histologic evidence of gastric, small bowel, and colonic mucosa, as well as respiratory epithelium and pancreatic tissue.